1. Field of the Invention
The present invention relates to an RF tag which performs data communication (reception and transmission) by wireless communication. The present invention relates to, in particular, an RF tag including a protection circuit which prevents element deterioration or destruction of a chip itself of the RF tag when a large amount of electric power is received by wireless communication.
2. Description of the Related Art
Nowadays, an individual identification technology using wireless communication (hereinafter referred to as a wireless communication system) has attracted attention. In particular, as a data carrier which communicates data by wireless communication, an individual identification technology with an RF tag (hereinafter, an RF tag referred in this specification is regardless of its shape such as a card shape or a chip shape) utilizing an RFID (Radio Frequency Identification) technology has attracted attention. The RF tag is also called an IC (Integrated Circuit) tag, an IC chip, an RFID tag, a wireless tag, or an electronic tag. The individual identification technology using a wireless chip has started to be used for production of an individual object, management, or the like thereof and has been developed to be applied to personal authentication.
A wireless communication system herein is a communication system which wirelessly exchanges data between a power supply source and transceiver such as a reader/writer and a transceiver such as an RF tag.
The wireless communication system does not need a physical connection between the reader/writer and the RF tag. That is, as log as the RF tag exists in a region specified by the reader/writer, data can be exchanged with the RF tag by communication between the reader/writer and the RF tag.
As for the reader/writer and RF tag, in order to extend the communication distance therebetween, research and development for increasing the power supply efficiency from the reader/writer to the RF tag has been activated (e.g., reference 1: Japanese Published Patent Application No. 2006-5651).